A heat pump water heater includes, to secure heating ability, improve heating efficiency and save energy for totally optimum operation control for a period including a winter defrosting time, a heat pump refrigerant circuit (30) having a compressor, a water refrigerant heat exchanger, an expansion valve and an air refrigerant heat exchanger, a hot water supply circuit (40) having a hot water reservoir tank, an internal circulation pump, a hot water supply mixing valve, a bath heat exchanger, a bath circulation pump and a hot water and water mixing valve for performing hot water storage in a tank, direct supply of hot water from the water refrigerant heat exchanger, hot water supply from the tank, filling a bathtub and additional heating of the bath and an operation control part (50) for performing an operation of hot water storage, an operation of directly supplying hot water, an operation of supplying hot water from the tank, an operation of filling the bathtub and an operation of additionally heating the bath by the operation setting of a hot water outlet remote controller (51) and a bathroom remote controller (52). The operation control part performs the optimum operation control for selecting one of three kinds of operating means including a heating efficiency prioritized operation, a heating ability prioritized operation and an intermediate defrosting operation based on an ambient temperature, an air refrigerant heat exchanger temperature and a hot water supply and storage mode as determination standard.